What MatchVolume is
MatchVolume is a macOS app that analyzes the loudness of each track in your music library and writes a Sound Check tag (iTunNORM) to the file so that playback volume is leveled.
- The audio data itself is never changed (non-destructive). You can revert at any time.
- It levels to the same reference as Apple Music (about −15.83 LUFS), so your tracks sit comfortably alongside Apple Music songs.
- The values it writes also carry over to iPhone, iPad, and Apple TV via Sync Library (turn on Sound Check on each device).
LUFS is an international unit for measuring perceived loudness in a way that reflects how we actually hear.
Key features
- Analysis (free) — measures each track’s loudness using EBU R128 / ITU-R BS.1770 (LUFS).
- Prediction and preview (free) — hear the volume with the recommended gain applied, using a dedicated engine, before you commit.
- Writes Sound Check tags — applies the calculated gain as an iTunNORM tag to level playback.
- Per track or per album — per album, it levels the album as a whole while preserving the relative differences between tracks (great for live albums, suites, and concept albums).
- Search — filter by title, artist, or album, ignoring full-width/half-width, case, and accent marks.
- Status display — see at a glance what is analyzing, applied, skipped, or not yet applied.
- Reasons for tracks that can’t be analyzed — the list and the detail panel show why (format or damage / no access / file missing) and what to do.
- Progress and Stop — the status bar shows the progress of analysis, applying and reverting, and Stop (⌘.) halts it at any time.
- Fast analysis and list — tracks are analyzed in parallel, so even large libraries finish quickly, and scrolling and sorting a list of tens of thousands of tracks stays smooth.
- Override and revert — replace existing Sound Check values with your own, and revert to the pre-application state in one click.
- Carries over to other devices — the values you write follow you to your other devices via Sync Library.
- Automatic exclusions — cloud-only, DRM, Apple Music, purchased, and effectively silent tracks are skipped automatically.
How it works (3 steps)
- Analyze — measure the track’s loudness and calculate the gain needed to level it.
- Apply gains — write the calculated gain to the file as an iTunNORM tag.
- Play — the Music app reloads, and playback with Sound Check turned on is leveled.
Tip: analysis, prediction, and preview are free. In the trial you can apply gains to any 10 tracks; the full version (a one-time purchase) unlocks applying to your whole library.
Usage guide (the interface)
Toolbar
- Reload Library — re-reads your Music library (reflecting added or changed tracks).
- Grant Folder Access — to read and write tracks outside
~/Music(such as on an external disk), sandbox restrictions require you to select that folder and grant access. Once granted, it is remembered. If some tracks are still outside the folders you chose, MatchVolume tells you how many and where they are. - Analyze Selected / Analyze All — analyzes loudness in bulk.
- Apply Gains to Selected / Apply Gains to All — writes the corrections (with a confirmation dialog).
- Revert Gains for Selected / Revert Gains for All — restores the values from before MatchVolume was applied.
When the window is narrow, the toolbar uses smaller buttons, or icons only (hover over an icon to see its name).
Leveling Unit
- Unchecked: levels each track to the reference (per track).
- Checked: groups by album and levels the album as a whole, preserving the differences between tracks within the album.
Search
Filter by title, artist, or album. Full-width/half-width, case, and accent marks are ignored.
Status column
| Indicator | Meaning |
|---|---|
| Spinner | Analyzing / applying |
| ✅ | Applied (an album shows ✅ when every applicable track in it has been applied) |
| 🚫 | Skipped (cloud-only / DRM / Apple Music / purchased, and albums where every track is skipped) |
| (blank) | Not yet applied |
Loudness column
| Indicator | Meaning |
|---|---|
| number | The measured loudness (LUFS) |
| … | Analyzing |
| — | Not analyzed yet |
| Silent | Effectively silent; skipped |
| Can’t analyze | Unsupported format, damaged or cut short, no permission to read the file, etc. |
| No access | Outside the folders you granted. Use Grant Folder Access to grant its folder |
| File missing | The file can’t be found (moved, deleted, or the external disk isn’t connected) |
| (Excluded: reason) | Out-of-scope tracks (cloud-only, DRM-protected, Apple Music, iTunes Store) |
After you grant the folder or connect the disk, tracks shown as No access or File missing can be analyzed again with Analyze All.
Detail panel
Shows the selected track’s current loudness, True Peak, recommended gain, predicted adjusted value, and any existing Sound Check value. Use the “?” on each item for an explanation.
Progress and Stop
While analyzing, applying or reverting, the status bar at the bottom of the window shows the progress (for example, Analyzing 120/3000). Click Stop (⌘.) next to it to halt. The track in progress is finished; tracks not yet started are left as they were. If you quit while files are being written, MatchVolume finishes the file it is writing before it quits.
Preview (leveled)
Hear the volume with the recommended gain applied, played through a dedicated engine (this lets you confirm the intended volume even around the macOS 26 and 27 behavior described below). Cloud-only and DRM tracks cannot be previewed.
About Sound Check playback on this Mac (macOS 26 and 27)
On some macOS versions, Sound Check playback in the Music app has a known OS-side behavior.
- On macOS 26 and 27, during local playback Sound Check can be over-applied (about 2×), so volume differences may widen or even invert. This is an OS-side behavior that occurs regardless of whether a tag is present (confirmed on macOS 26.5.1, 26.6, 27.0 and 27.0.1).
- The values MatchVolume writes are correct, and on iPhone / iPad playback is leveled correctly via Sync Library. Playback on this Mac will become correct automatically once Apple resolves it.
Correction Mode (shown only on macOS 26 and 27)
On macOS 26 and 27, choosing “For macOS 26 / 27” from the Correction Mode menu writes half the value to match that Mac’s local playback (the 2× over-application). In all other environments (including iPhone), “Standard” is correct, so this menu appears only on macOS 26 and 27.
Carrying over to iPhone / iPad / Apple TV
If you turn on Sync Library on your Mac and iPhone / iPad, the iTunNORM that MatchVolume writes syncs to your other devices, and playback is leveled in the standard Music app. Turn on Sound Check on each device.
- Where to find Sync Library: on Mac, Music ▸ Settings ▸ General in the Apple Music app; on iPhone / iPad, the Settings app ▸ Music.
- For the conditions for using Sync Library and how your library appears on Apple TV, see Apple Support’s article on Sync Library.
Note: extremely quiet tracks (roughly below −28 LUFS) may not level completely because of the iOS volume-boost ceiling (about +12 dB). Ordinary tracks are unaffected.
Supported formats and skipped tracks
Supported formats: AAC / M4A, MP3, AIFF, and Apple Lossless (ALAC) — all support tag writing. Surround tracks such as 5.1 and 7.1 are measured with ITU-R BS.1770 channel weighting according to each file’s channel layout.
Skipped: cloud-only (no local file), DRM-protected, Apple Music (subscription), iTunes Store purchases, and effectively silent tracks. WAV is skipped because it has no standard tag for holding correction data.
Trial and purchase
- Analysis, prediction, and preview are all free.
- Applying gains (writing) is free for any 10 tracks in the trial. A trial slot you have used is not restored even if you revert.
- A one-time, non-consumable in-app purchase unlocks applying gains to your whole library. Prices are shown in your regional App Store currency (for example, ¥4,000 in Japan / $24.99 in the US).
- If you end up in an unpurchased state after changing devices, sign in with the Apple Account used for the purchase and choose “Store ▸ Restore Purchases.”
Privacy
MatchVolume has no data collection and no telemetry. The app contains no networking code. Analysis and writing happen entirely on your Mac, and no track information or analysis results are sent anywhere. The only connection is for in-app purchases, which Apple’s StoreKit handles with Apple; none of that data reaches us.
Frequently asked questions
Q. I applied gains, but volume isn’t leveled on this Mac. A. This may be the OS-side behavior in macOS 26 and 27. The values written are correct, and they level correctly on iPhone / iPad. Use “Preview (leveled)” in the app to hear the intended volume.
Q. Does the same problem happen on macOS 27? A. Yes. We measured it on macOS 26.5.1, 26.6, 27.0 and 27.0.1, and Sound Check was over-applied by about 2× on all of them. MatchVolume shows the notice on macOS 27 as well, and offers the “For macOS 26 / 27” correction mode.
Q. Some tracks show “Can’t analyze”, “No access” or “File missing”. A. Select the track to see the reason and what to do in the detail panel. “No access” means the file is outside the folders you granted; use Grant Folder Access to grant that folder. “File missing” means the file was moved or deleted, or its external disk isn’t connected. In both cases, analyze again with Analyze All once the cause is fixed. “Can’t analyze” means the file may be damaged or in a format macOS doesn’t support; no gain is applied to it.
Q. Can I stop analysis or writing partway through? A. Yes. Click Stop (⌘.) in the status bar. The track in progress is finished; tracks not yet started are left as they were.
Q. The tags I wrote disappeared. A. iTunNORM can be lost through other tag editors, re-importing tracks, or re-downloading via iTunes Match. This is not something MatchVolume does. Because analysis results are cached, you can apply gains again without re-analyzing.
Q. What about WAV? A. WAV has no standard tag for holding correction data, so it is not supported.
Q. Does it reduce audio quality? A. No. MatchVolume never changes the audio data; it only writes a tag indicating the reference playback volume (non-destructive). You can also revert.
Q. What about privacy? A. There is no data collection. The app contains no networking code, and analysis and writing happen entirely on your Mac. Only in-app purchases involve a connection, which Apple’s StoreKit handles with Apple; none of that data reaches us.
Requirements
- OS: macOS 15 Sequoia or later
- Required app: Apple Music / the Music app
- Device sync: Sync Library (when syncing to other devices)
- Display languages: Japanese / English (switchable in the app)